Ewings sarcoma arises from

Refer Robbins page no 8/e 1232 Ewing sarcoma is a malignant bone tumor characterized by primitive round cells without obvious differentiation. Recently, Ewing sarcoma and primitive neuroectodermal tumor (PNET) have been unified into a single category: the Ewing sarcoma family tumors (ESFT) based on shared clinical, morphologic, biochemical and molecular features (discussed later). Although PNET demonstrates more neu- roectodermal differentiation than Ewing sarcoma, the dis- tinction is not clinically significant